JPH05291361A - Lead structure of semiconductor device - Google Patents

Abstract

PURPOSE:To effectively lighten thermal stress which occurs in the lead connection part after mounting a semiconductor chip on a semiconductor substrate. CONSTITUTION:In a semiconductor device 1, where a semiconductor chip 2 connected to the inner lead 4 patterned on a base film is mounted, the inner lead 4 cut in a specified length is so bent and shaped along the semiconductor chip 2, whereby one end 4a of the inner lead 4 connected to the bump 3 of the semiconductor chip 2 and the other end 4b connected to a board 5 are separated in the height direction. Though the inner lead 4 is bent in, for example, U shape, the thermal stress can be lightened surely since it has effective length in the height direction from the board 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, in which a semiconductor chip is bonded and connected to leads formed by patterning on a base film, and more particularly, TAB (Tape Automated).
The present invention relates to a semiconductor device lead structure suitable for a bonding package.

[0002]

2. Description of the Related Art In recent years, electronic devices such as computers have been required to be smaller and lighter. Therefore, there are semiconductor chips used in electronic devices mounted on a flexible tape made of resin or the like. As the above, a mounting method called a beam lead is known. FIG. 9 shows a configuration example of a semiconductor package mounted by a conventional beam lead method. In the figure, in a semiconductor package 21, leads 24 are bonded and connected to a semiconductor chip 22 via bumps 23. An electrode 26 forming a predetermined electric circuit is formed on the substrate 25, and the semiconductor package 21 is mounted by connecting the tip end of the lead 24 to the electrode 26.

[0003]

In the conventional semiconductor device mounted by the beam lead method, in particular, the leads 24 extend laterally from the semiconductor chip 22 in a substantially straight line shape as shown in the drawing, and the substrate 25 remains as it is. Electrode 26
It is designed to connect with. That is, the distance h in the height direction from the substrate 25 between the bump 23 connecting portion and the electrode 26 connecting portion of the lead 24 is extremely small or h≈0. Since the leads 24 are arranged in a planar and linear manner in this way, thermal stress is generated in the connection portion of the leads 24 due to heat generation of the substrate 25, and this thermal stress can be relaxed / absorbed. could not.

That is, it is considered that the cause of the thermal stress is mainly due to the difference in the coefficient of thermal expansion among the semiconductor chip 22, the leads 24, and the substrate 25 or the electrode 26.
Due to the heat generated when the semiconductor chip 22 etc. operates,
For example, tensile stress is generated between the leads 24 on both sides of the semiconductor chip 22. Since the lead 24 is linear, such tensile stress cannot escape. For this reason, when a lead structure such as a beam lead system is adopted in the pattern forming TAB system with a large number of thin and fine leads on the base film, breakage or breakage particularly occurs in the bump 23 portion and the connection portion with the electrode 26. It was dangerous and it was difficult to prevent them effectively.

In order to solve the above problems, it is an object of the present invention to provide a lead structure of a semiconductor device which can effectively alleviate the thermal stress generated in the lead connecting portion after the semiconductor substrate is mounted.

[0006]

A lead structure for a semiconductor device according to the present invention is a semiconductor device in which a semiconductor chip is connected to one end of a large number of leads patterned on a base film and cut into a predetermined length. Is formed between the other end of each lead connected to the mounting board and one end of each lead connected to the semiconductor chip, and one end and the other end of each lead are formed. And are separated from each other in the height direction.

Further, in the lead structure of the semiconductor device according to the present invention, each of the leads is formed by bending along the outer periphery of the semiconductor chip from the upper side to the lower side of the semiconductor chip, and the semiconductor device is faced to the mounting substrate. It is desirable that it be implemented in an up-system. Further, it is also preferable that each of the leads is formed by bending under the semiconductor chip, and the semiconductor device is mounted on the mounting substrate by a face-down method.

Further, in the lead structure of the semiconductor device according to the present invention, it is desirable that the lead is bent and formed into a substantially U shape or an arc shape.

More preferably, the other end of each lead is cut at the position where the base film remains.

Further, it is desirable to interpose an insulating material between the semiconductor chip and each of the leads.

[0011]

According to the present invention, the lead punched out to a predetermined length is connected to the mounting board, and the lead is bent and formed as described above, whereby one end of the lead and the other end thereof are formed. And are separated from the mounting substrate in the height direction. Even if thermal stress occurs in the connecting portion of the lead with the mounting board, the lead has an effective length in the height direction from the mounting board, and therefore absorbs the thermal stress applied in this height direction portion. And it can be prevented from transmitting. Further, the inner leads on both sides sandwiching the semiconductor chip do not exert a tensile action on each other, and as a result, tearing of the inner leads can be reliably prevented.

When the leads are formed by bending, the leads are formed by bending along the outer periphery of the semiconductor chip from the upper side to the lower side of the semiconductor chip, which is extremely effective in mounting in a face-up system. Target.
In addition, since each lead is bent and formed on the lower side of the semiconductor chip, it is extremely effective when mounted in a face-down method.

In any of the above cases, the lead can be bent and formed into a substantially U-shape or an arc shape. However, such a bent shape is relatively easy to form and exhibits excellent effects. it can.

Further, by cutting the other end of each lead at a position where the base film remains, it is possible to ensure convenience in handling the lead after cutting, and at the same time, ensure proper lead and mounting substrate. There are advantages such as ensuring a secure connection. Further, by interposing an insulating material between the semiconductor chip and each of the leads, it is possible to obtain insulation and strength.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the lead structure of a semiconductor device according to the present invention will be described below with reference to FIGS. Although FIG. 1 shows a mounting example of the TAB package 1, the semiconductor chip 2 is bonded to the inner leads 4 via the bumps 3. Electrodes (not shown) forming a predetermined electric circuit are formed on the substrate 5. The inner lead 4 is bent and formed so as to be routed from the upper side to the lower side of the semiconductor chip 2 along the outer periphery, but in this example, it is formed in a substantially U-shape as shown in the drawing. Also,
The bumps 3 of the semiconductor chip 2 are located on the upper surface side of the semiconductor chip 2 (a so-called face-up method), and one end portion 4a
The other end 4b of the inner lead 4 connected to the bump 3 is connected to the electrode, and thus the TAB package 1 is mounted on the substrate 5. In this way, the end portion 4a of the inner lead 4 on the bump 3 side and the end portion 4b on the substrate 5 side are separated from the substrate 5 in the height direction. Incidentally, as shown in the figure, a part of the semiconductor chip 2 has a resin 6 for insulation.
However, the resin 6 can be provided in advance before the inner lead 4 is formed into a U-shape.

FIG. 2 shows a structural example of the TAB package 1 used in this embodiment. In the drawing, the inner lead 4 and the outer lead 8 are patterned on a base film 7 made of polyimide or the like, The inner lead 4 is bonded and connected to the semiconductor chip 2 as described above. A support ring 7 composed of the base film 7 is provided between the inner lead 4 and the outer lead 8.
a is provided, and the inner lead 4 is punched out along the parting line 9 inside the support ring 7a (see FIG. 2, dashed line) or along the parting line 10 inside the support ring 7a (see dotted line in FIG. 2). The processed one is used. Thus, the inner lead 4 can mount the TAB package 1 as shown in FIG. As is clear from the above description, the inner lead 4 in this embodiment is formed sufficiently longer than the normal inner lead in the TAB method, and the inner lead 4 has the function of the normal outer lead. ..

The lead structure of the semiconductor device according to the present invention is constructed as described above, and its operation will be described below.
As shown in FIG. 1, the inner lead 4 is bent and formed in a U shape so that the end 4 a of the inner lead 4 on the bump 3 side and the end 4 b of the mounting substrate 5 side are formed on the substrate 5.
Are separated by a distance H in the height direction. Since the inner lead 4 has an effective height direction portion between the end 4a and the end 4b as described above, the end 4a and the end 4a which are the connecting portions of the inner lead 4 to the semiconductor chip 2 and the substrate 5 are Even if thermal stress is generated in 4b, it is possible to absorb the thermal stress applied in the height direction portion and prevent the thermal stress from being transmitted. That is, the inner leads 4 on both sides of the semiconductor chip 2 do not exert a tensile or compressive action on each other, and thus it is possible to reliably prevent the inner leads 4, particularly the end portions 4a and 4b from being damaged. it can.

In the above case, when the inner leads 4 are punched along the parting line 10, the ends of the respective punched inner leads 4 are connected to each other by a part of the support ring 7a. The portion of the support ring 7a as shown by the dotted line in FIG. 1 is arranged inside the U-shaped inner lead 4. By punching the inner leads 4 so that the polyimide material forming the support ring 7a remains in this way, it is possible to prevent the alignment state of many inner leads 4 from being disturbed after the punching. As a result, the bending forming process for the inner leads 4 can be performed easily and surely, and the plurality of inner leads 4 that are grouped together are very convenient to handle.

3 and 4 show a second embodiment of the lead structure of the semiconductor device according to the present invention. In the second embodiment, the inner lead 4 is bent and formed in a substantially U-shape as in the case of the first embodiment, but the inner lead 4 is arranged below the semiconductor chip 2 as shown in the drawing. The bumps 3 of the semiconductor chip 2 are mounted so that they are located on the lower surface side of the semiconductor chip 2 (so-called face-down method). When the inner lead 4 is formed by bending,
The inner lead 4 can be formed into a U shape by using an appropriate jig 11 as shown in FIG.

Also in the second embodiment, the inner lead 4
Since the end portion 4a on the bump 3 side and the end portion 4b on the substrate 5 side are separated by a distance H in the height direction of the substrate 5, similar to the case of the first embodiment, tearing of the inner lead 4 or the like occurs. Can be effectively prevented. And according to this second embodiment,
Particularly, since the inner leads 4 are arranged substantially in the lower region of the semiconductor chip 2, there is an advantage that the mounting space of the semiconductor device can be reduced. After mounting the TAB package 1 on the substrate 5, the whole may be sealed with the resin 12 by a method such as potting.

5 and 6 show a third embodiment of the lead structure of the semiconductor device according to the present invention. In this embodiment, the inner lead 4 is formed in an arc shape or a curved shape close to this, and the case of FIG. 5 corresponds to the first embodiment and the case of FIG. 6 corresponds to the second embodiment. .. Other basic configurations are the same as those of the first or second embodiment, and detailed description thereof will be omitted here. Also in this third embodiment, it is possible to obtain the same effect as that of each of the above embodiments.

7 and 8 show a fourth embodiment of the lead structure of the semiconductor device according to the present invention. In this embodiment, the inner lead 4 is bent and formed under the semiconductor chip 2 so that the inner lead 4 is concave outward. In this case, the bent shape of the inner lead 4 can be formed in a U shape (FIG. 7) or an arc shape (FIG. 8), but the inner lead 4 needs to extend inward from the bump 3. Therefore, a relatively large semiconductor chip 2 is suitable for obtaining such an inner lead 4.

In addition to the above-mentioned embodiments, the inner lead 4 can be bent and formed into, for example, a dogleg shape or an appropriate curved shape, and is not limited to the illustrated embodiment, but in any case. Also, the same effects as those of the above-described respective embodiments can be obtained.

[0024]

As described above, according to the lead structure of the semiconductor device of the present invention, when the semiconductor device is mounted on a semiconductor substrate or the like, by effectively relieving the thermal stress generated in the lead connection portion after mounting the substrate, the leads can be formed. It has excellent protective effects such as the ability to reliably prevent tearing and the like.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a mounted state of a semiconductor device according to a first embodiment of a lead structure of a semiconductor device of the present invention.

FIG. 2 is a plan view showing a configuration example of a TAB package used in the semiconductor device of the present invention.

FIG. 3 is a vertical cross-sectional view showing a mounted state of a semiconductor device according to a second embodiment of the semiconductor device lead structure of the present invention.

FIG. 4 is a vertical cross-sectional view illustrating a step of forming a lead structure according to the second embodiment.

FIG. 5 is a vertical cross-sectional view showing a mounted state of a semiconductor device according to a third embodiment of the semiconductor device lead structure of the present invention.

FIG. 6 is a diagram showing a modification of the third embodiment of the present invention shown in FIG.

FIG. 7 is a vertical cross-sectional view showing a mounted state of a semiconductor device according to a fourth embodiment of the semiconductor device lead structure of the present invention.

FIG. 8 is a diagram showing a modification of the fourth embodiment of the present invention shown in FIG.

FIG. 9 is a vertical cross-sectional view showing a mounted state of a conventional semiconductor device with a lead structure.

[Explanation of symbols]

 1 TAB Package 2 Semiconductor Chip 3 Bump 4 Inner Lead 4a One End 4b Other End 5 Substrate 6 Resin 7 Base Film

Claims (6)

[Claims] 1. A semiconductor device in which a semiconductor chip is connected to one end of a large number of leads patterned on a base film, the other end of each lead being cut to a predetermined length and connected to a mounting substrate. A portion and one end of each of the leads connected to the semiconductor chip are formed by bending, and one end and the other end of each of the leads are separated in the height direction. Structure of semiconductor device. 2. The respective leads are formed by bending along the outer periphery of the semiconductor chip from the upper side to the lower side of the semiconductor chip, and the semiconductor device is mounted on the mounting substrate in a face-up method. The lead structure for a semiconductor device according to claim 1. 3. The leads are bent and formed on the lower side of the semiconductor chip, and the semiconductor device is mounted on the mounting substrate by a face-down method.
The lead structure of the semiconductor device according to 1. 4. The lead structure for a semiconductor device according to claim 1, wherein the lead is bent and formed into a substantially U-shape or an arc shape. 5. The lead structure of a semiconductor device according to claim 1, wherein the other end of each lead is cut at a position where the base film remains. 6. The lead structure of a semiconductor device according to claim 1, wherein an insulating material is interposed between the semiconductor chip and each of the leads.